where operators connect to their customers,” the ONF says. “CORD is a project intent on transforming this edge into an agile service delivery platform enabling the
operator to deliver the best end-user experience along with innovative next-generation services.

The VOLTHA 1.0 release is a notable
milestone for the CORD project. AT&T’s
Barker stated that major software releases
like it “are necessary to fulfill our vision
of a software-defined network, which
employs NFV. We expect to have 55 percent of our networks virtualized by the
end of 2017. We aim to have 75 percent of
our traffic on our software-defined network by 2020, and we’re pushing hard to
beat that goal.

“Open software efforts benefit the industry because we rely on the active participation and feedback form a large
community of developers,” he added.

“Developers can improve, add, and in-fluence changes to the software thatwill help us deliver XGS-PON technologyto customers quickly. We are currentlyperforming proof-of-concept testing ofVOLTHA in our labs and are planningto deploy XGS-PON field trials before theend of 2017.”

How POL fits

Back to the chat with the Tellabs salesexec who mentioned passive opticalLAN and SDN in the same sentence … itwill be a very long time before anythinglike VOLTHA makes its way into main-stream enterprise networking. But SDNis a timely topic for the LAN. In a docu-ment aimed at federal-government us-ers, Tellabs declares that passive opticalLAN offers the best architecture for soft-ware-defined LANs. It explains that asgovernment network administrators eval-uate the merits of SDN functionality inbuildings and across campuses, they aredoing so “under the assumption that SDNfixes traditional LAN operational efficien-cies, security and reliability shortcomings.However, what they don’t realize is that bybolting-on SDN as an overlay to a legacyLAN design, they leave the inherent weak-ness of traditional LANs.”Pointing the finger at the traditionalLAN architecture, Tellabs further con-tends, “Adding complexity with SDN canmarginally improve LAN operational effi-ciencies, security and reliability, but by in-troducing more sophistication, the fixescan negatively contribute to the same at-tributes they were intended to repair.Furthermore, there are alternative meansof addressing the underlying fundamentalfaults relative to traditional LAN … thatspecifically fix root problems.”Passive optical LAN, Tellabs explains,is one such alternative means. The com-pany points out the following potentialpitfalls of implementing SDN as an overlayto a traditional LAN.

Conversely, Tellabs argues, an optical LAN “marries the best features of passive optical networking with advanced
Ethernet functionality. It does so within
the framework that matches cloud, wireless, hosted/managed services, data center and SDN architecture—all of which
have the common trait of having centralized intelligence and management.”
Plus, a passive optical LAN can define
network resources in software, and dynamically allocate them based on real-time demands.

Furthermore, the company stresses,passive optical LAN facilitates SDN im-plementation in part because “simple un-managed ONTs [optical network termi-nals] are better suited for SDN ratherthan complex full-functioning traditionalswitches,” and because a passive opticalLAN “will allow a mixture of G-PON, XGS-PON, and NG-PON2 [40G] technologychoices simultaneously, without the rip-and-replace of today’s infrastructure.”As IBM’s white paper pointed out, op-tics changed service-provider networksin the 1980s. It was about 2010 when pas-sive optical LAN technology took hold inenterprise networks. It may be decadesbefore the fruits of the ONF’s efforts areenjoyed by enterprise networks—if theyever are. Nonetheless, proponents of pas-sive optical LANs are pointing to historyto make their case for what the futurewill hold. u